The present invention relates to conveyors, and more particularly to conveyors that manipulate articles. The invention may be applied in many ways, including by way of example, to separate batches of parcels by releasing parcels one at a time. Another application is to manipulate a stream of articles by delivering the articles one at a time with generally controlled gaps between the articles. The articles may also be aligned, such as lengthwise.
Conveyors—such as belt conveyors, roller conveyors, and other types of conveyors—are in widespread use today for moving packages, parcels, mail, boxes, and other articles from one place to another. In many situations the articles that are to be carried by the conveyor are initially placed on a conveyor in a manner that is not conducive to being transported and processed by the conveyor system. Typically, the conveyor system is set up to optimally transport articles when they are arranged in a single-file line. In many situations, articles enter a conveyor system on conveyors that are sufficiently wide to accommodate multiple articles positioned side-by-side. In order to effectively process these side-by-side articles, it is desirable to manipulate them such that they are no longer arranged side-by-side, but rather in a single-file line. It may also be desirable to provide controlled gaps between the articles and to orient the articles in a particular manner, such as lengthwise.
In the past, several different types of article manipulators have been used, but these all contain features that have room for improvement. For example, PCT Application Serial No. PCT/US00/11370 (Publication No. WO 01/74693) discloses a hold and release singulator for manipulating items being transported. The hold and release singulator operates in a batch like fashion. In other words, groups of articles are transported onto the singulator, then stopped, and then individually caused to exit the singulator one at a time. After all of the articles have exited the singulator, another batch of articles is moved onto the singulator and the process is repeated. This method may produce an uneven flow of articles exiting the singulator. Further, a batch type manipulation process may not manipulate items as fast as a continuous process.
A continuous type of manipulation process is disclosed in European patent publication EP 0 979 788 82 (application number 99250264.1). However, not all items that enter the singulator of this patent will necessarily be manipulated during their first transport over the manipulation bed. The manipulation device disclosed in this patent includes a return section 70 in which non-manipulated items are re-circulate though the singulator. The re-circulation of these items is generally inefficient. Further, additional floor space must be provided to accommodate the re-circulation conveyors. Oftentimes factory floor space is at a premium and the use of additional space is desirably avoided.
PCT patent application serial no. PCT/US01/13556 (Publication No. WO 01/83339) discloses another existing type of article singulator. While the application discloses several different embodiments of an article singulator, none of these embodiments disclose a singulator which rotates articles. In addition to manipulating articles into a single file line, it is often desirable to rotate the articles such that their longitudinal axis is generally parallel to the longitudinal axis of the conveyor. The articles that enter a singulator are customarily oriented at all different angles. When a singulator is used, such as that disclosed in PCT application PCT/US01/13556, the orientation of the articles are not altered using the singulator. The articles therefore must be processed having skewed angular orientations, or additional means must be provided to rotate the articles to a desired orientation.
In light of the foregoing disadvantages with several of the prior art singulators, the desire can be seen for an improved singulator that overcomes these and other disadvantages.